Aldose reductase is the first enzyme in the polyol pathway and catalyzes the reduction of glucose to sorbitol by coupling with the oxidation of NADPH to NADP+. This sorbitol accumulation leads to various diabetic complications, including neuropathy, nephropathy, cataracts, and retinopathy. In the present study, aldose reductase inhibitory (ARI) activity of the methanolic as well as standardized extracts ofAndrographis paniculata(Burm. f.) Wall. ex Nees (Acanthaceae) and its chief constituent, andrographolide, were studied usingin vitroandin vivomethods. In thein vitromethod, rat lens as well as kidney homogenates were used for the preparation of enzyme, whereas the effect of these test samples on the galactitol level in the eye lens was studied in a galactosemic rat modelin vivo. The results of the study revealed that both extracts of the plant and its major compound, andrographolide, possess ARI activityin vitro. They were also found to significantly decrease galactitol accumulationin vivo.